This invention relates to buoyancy compensators carried by divers for swimming under the surface of water, for example, scuba diving.
Buoyancy compensators are well known as auxiliary means for adjustment of buoyancy equilibrium during activity under the surface of water as well as surfacing in emergency. Such well known buoyancy compensators include the type in which a vest in the form of an air bag is equipped with a harness used to carry an air cylinder on the back of a diver and the type in which there are provided on the shoulders of such vest length-adjustable and detachable shoulder straps. FIGS. 5 and 6 are front and rear perspective views, respectively, exemplarily showing the buoyancy compensator of the latter type. This buoyancy compensator of the prior-art is so constructed that air supply from an air cylinder (not shown) to a vest 3 and exhaust from the vest 3 to the outside thereof may be selectively controlled via an inflation hose 9 or the like. The air cylinder is integrally attached to the vest 3 by means of the harness 10 so that the air cylinder may be carried on the back of a diver as the vest 3 is put on. The harness 10 comprises plastic moldings or semi-hard flexible plate-like material curved so as to fit the externals of the air cylinder and provided with bands 7 and buckles 8 used to hold the air cylinder. Such harness 10 is screw-clamped to or sewed on the back side of the vest 3. The vest 3 is provided along a waist line with belts 4 attached to waist portions 13 which may be fastened to make the waist line of the vest 3 fit around the diver's body. The waist portions 13 are connected to each other with straps 12. Shoulder straps 5, 6 may be adjustably fastened to make it fit about the diver's shoulders.
While such a buoyancy compensator of prior art is convenient in that the waist belt and the shoulder straps may be length-adjusted to make the compensator fit on the diver's body, size-adjustment relying on the waist belt and the shoulder strap has a limitation. Consequently, the buoyancy compensators of disadvantageously various sizes must be produced and stocked to meet the demand. This problem is very serious in view of a trend that the buoyancy compensator and accessories thereof become more and more colorful and the number of items correspondingly increases.
The air cylinder normally weighs ten-odd Kg and therefore the waist belt as well as the shoulder strap must be tightly fastened so as to make the vest fit on a diver's body and thereby to carry the air cylinder tightly on the diver's back. Generally, the vest comprises two sheets of texture placed one on another and air-tightly sealed around the peripheral edge of the sheets thus placed one on another so that both sheets may be inflated in opposite directions. However, with the vest being in close contact with the diver's body, inflation toward the diver's body is necessarily restrained. As a consequence, the buoyancy expected from the specified capacity of the vest can not be obtained and the diver experiences a sense of compression.
While the main components of the buoyancy compensator can be assembled by a series of sewing operations, the buoyancy compensator of the prior art comprising almost all components integrally assembled together becomes bulky as the assembling process proceeds to the second half thereof and productivity reduces due to the troublesome operation of sewing.